Grinders

O

Old oak

Joined
Jul 14, 2019
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I know it’s been beat to death on every thread and I’m going to get a million answers. Here’s the situation which everyone has been in also.

Been making knives for a few years now and been using cheap 4/36” belt grinders from the big box stores and about to have to roll into grinder number 3... mostly do flat grinds on forged blades. I try to keep the stock removal to a minimum so the wife doesn’t complain about dust all over the garage.

Any suggestions up to around 500$ or so for a half decent 2/72”?

I have a 1.5hp 3450rpm single phase delta motor on my table saw that is about 15 years old I can switch back and forth if I’m buying a setup without a motor.

I’m also half decent at fabrication of just about anything as long as I have the time (2 young kids).

Given those options would y’all recommend a motorless unit and adding mine to it or just getting something like a grizzly ready to go and just work with it. Got a whole box full of knives made off the cheap grinders so I would imagine just about anything is better than using the 4/36”

Alright bring on the suggestions.
 
Yeah I could probably make something like that but again 2 kids under 6 so it’s like being in a prison riot around here. Not enough time to sit down and make something that pretty... wanna make me one? Probably have more time than me. I’m down to cranking out a knife or two every couple months or so now.

What size motor did you use. I’m assuming that since mine is 3450 rpms i would have to gear it down a bit to get it slow enough to not destroy something.
 
My kids were 9 & 6 at the time, and most of the time you don’t want to know what my work schedule looks like. I can usually turn out 4-6 knives a year with the majority of the work being done in February and the finishing taking place over the rest of the year.
I think I got lucky and it turned out right.
My motor is a 2hp at 1760(IIRC), I wish I had more speed.

You can change your SFPM with the diameter of your drive wheel, a belt and pulley drive setup, or a VFD.
 
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3fifty7 said:
I made mine based off of these plans and it runs great, just need to add a VFD one of these days.

http://dcknives.blogspot.com/p/2-x-72-belt-grinder.html?m=1

If posting this link isn’t kosher I’ll remove it.

View attachment 1162566
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If this is mine grinder I will add lock bolt to tension arm ......will make huge difference .
CoTbp9K.jpg
 
Both Origin Blade Maker and Kadrmas Kreations have 2x72 belt grinders without motors for under 500$ before shipping. I have the SRG Kadrmas... it's not supper beefy (when compared to a TW-90 or something along those lines), but it's worked really well for my needs thus far. I don't have much to compare it to though since it's my first "big boy grinder".
 
So looked at these suggestions. I like the Coote because of the simple stupid shouldn’t break philosophy. Also like that it comes with the larger wheel and don’t have to come up with a separate attachment for that. Anyone that has one of these let me know any downfalls or pluses?
 
Natlek said:
If this is mine grinder I will add lock bolt to tension arm ......will make huge difference .
Click to expand...

What problem would that solve or improve?

I know some grinders have a locking ratchet tension system, but I’ve used a few with spring or gas piston tensioners and never thought, “man I really need to lock the tension in place”.
 
Natlek said:
If this is mine grinder I will add lock bolt to tension arm ......will make huge difference .
CoTbp9K.jpg
Click to expand...
I made the same grinder. Took me about 3 days time to do. Got a second hand 220v 3 phase motor and cheap vfd and I am under $500 total. Haven't found any need for a lock bolt. Thing runs fine and spring keeps tension on.
 
Im just a northern tool fanboy. I love their grinder! Save pennies. You've been using an old grinder for how long? Buy once, cry once. One of the best pieces of advice I've gotten
 
Randydb said:
What sort of difference do you think the lockbolt would make Natlek?
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Tracks better , working with slack belt ,belts last longer . First and most important will not change tension on belt . When you push really hard into the platen, with a spring like that on your grinder , the belt can move to the side . When pushing hard on the platen traps the belt with friction and the spring arm will actually move with the change of belt tension making the belt move to one side ...
 
Natlek,
I disagree with that analysis. Trapping the belt under pressure at the platen will make the drive wheel push more slack toward the tracking/tension wheel arm. If the tracking/tension arm is locked with a bolt, it will make the belt looser between the drive wheel and the platen, thus allowing the belt to drift. If there is a spring pushing the arm the arm will lengthen and keep roughly the same tension as before.

I think that a spring or gas shock is fine for most basic grinders. Large heavy duty grinders might use a ratchet tension arm because they use much higher tension in some cases, as well as speedy belt changes.

On this particular build, the trapped spring provides constant tension once the tool arm length is locked down. If more tension is needed, either the arm is moved out more, or a stronger spring is used (or a slug is dropped in the tube to increase the compression of the spring).
This is similar to the tension setting on Bader, KMG, etc. There are maybe a million grinders with similar tension and I never saw one that locked the tension arm once the tension was set. The lock bolt on those with a wheel only hold the tool arm in place to set the tension. The spring arm still moves up and down as needed. Locking the tension arm would defeat the reason for a tension spring.
 
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